Signal system for telephones



K. TSUKAMOT O.

SIGNAL SYSTEM FOR TELEPHONES.

APPLICATION FILED JUNE I2. I919.

. 1 3 5 5 1 9 1 Patented Oct. 12, 1920.

' at No. 53 Nichome, Iida Machi, I

states stares series.

ZKIZO TSUKAMOTO, or TOKYO, JAPAN, ASSIGNOR TU assassin: Karena rsUKAMo'ro- DENKI KENKYUSHO, 0F TOKYO, JAPAN.

SIGNAL SYSTEM FOR, TELEPHONES.

Specification of Letters Patent. Pgttnijed Oct, 12 192() Application filed June 12, 1919. Serial No. 303,556.

T 0 (LN 20 hom it may concern 2 Be it known that I, KIzo TsUKAMo'ro, subject of the Emperor of Japan re'siding iojimachi in, Tokyo, Japan, have invented new and useful Improvements in a Signal System for Telephones, of which the following is a specification.

This invention relates to a signal system for telephones in which the circuit through the secondary coil of the transformer and the line wires is closed at the same time whenthe circuitof the battery is connected with the primary coil of the said transformer, and a high tension current is sent to the signal system of the exchange oilice, only at the moment when the receiver is being taken oflf or hung on, the hook-lever. The object of this invention is to make it more suited for sending signals to a long distance, to simplify the construction of such a system, to economize the cost of manufacture and to reduce the consumption of electric current.

The accompanying drawings show a signal system for telephones embodying nay-in vention, in which- Figure 1 shows diagrammatically the circuit system when the receiver is hung on the hook-lever Fig. 2, circuit system at the moment when the receiver is being taken 05, or hung'on,

the hook-lever, and

Fig. 3, circuit system when talking over the telephone is going on. s

The same reference characters designate the same or corresponding parts throughout all the figures.

In the signal system according to my invention, one line wire (1) is connected to a I hook-lever (2), and the other line wire (1 to a contact piece (4:) lying below the hooklever (2), through the bells (3). One terminal of a wire (6) forming part of the circuit of the receiver (5) is connected to another contact piece (7) and the other terminal, to the line wire (1 through the secondary'coil (8) of an induction coil and a wire (9). The contact piece (7) which lies above the hook-lever (2) will be brought into contact with the latter when the receiver is taken old the hook-lever (2) then the wire (6) will be connected with the line wire (1) through the contact piece (7) and the hook-lever (2). i

The primary circuit of the transmitter consists of the transmitter (10), the primary coil (15) of an induction coil, and battery (1 1), conected in series by wires (11), (12) and (18). The free ends of the wires (11) and (12) are connected respectively with spring contact pieces (16) and (17); and when the receiver (5) is taken off the hook-lever (2), the primary circuit of the transmitter (10) is closed through the hook lever (2), as it then comes into contact with the spring contact pieces (16) and (17 Between the spring contact pieces (16) and (17), there are providedtwo more spring contact pieces (19) and (20), and the spring contact piece (16), having a cam lug (18), will be pushed back at a moment when the hook-lever (2) rises or falls down, and then the spring contact-pieces (16), (19) and (20) will be brought into contact with one another, and momentar'ilyclose the primary circuit of the signal system which consists of the spring contact piece (16), battery (14), the primary coil (P) of the transformer (22) and the spring contact piece (20). By means of the current thus caused in the primary circuitoi the system, signals are sent to the exchange oiiice through the circuit consisting of the lineswire (1), the hook-lever (2), spring contact pieces (16) and (19), the secondary coil (S) of thetransformer and the line wire (1 And as this signal giving current flowsonly a moment occurring during the rising or falling, motion of the hook-lever, the consumption of electricityis very small.

Claim: s

In a signal system for telephones, the combination of a hook-lever pivoted intermediate its ends and connected. with one of the line wires, a spring contact piece at the rear end of said hook and provided with a cam lug located in the path of the rear end of the lever during the movement of the latter, a pair of spring contact pieces adjacent to said first contact piece, a transformer having one end of its primary coils connected with the first contact piece and the other end with one of said pair of contact pieces, a battery connected in the circuit of said primary coil, the secondary coil of said transformer having one end connected with the other of said pair of spring contact pieces and the other end with one of the line wires. 10

In testimony whereof I have signed my name to this specification.

KIZO TSUKAMOTO. 

